I am having a really challenging time finding a compression method that will give me solidly smooth playback. For 95% of what I am doing, the occasional skipped frame is not an issue. I do, however, have one long animated pan that look awful with skipped frames. I've tried running isadora at 29.97, 30, 60fps, quicktime, and wmv:

1280X960 75% PJPEG 30fps, and 29.97 fps
960X720 same
720X540 same

I have also tried WMV using Windows media 9 advanced, 9, 8, and 7.

Nothing I have tried is giving me smooth playback. I am running this all off my G750JH from an SSD and GTX780M with 4GB vram.

These clips playback without a hitch in VNC.

At this point, I am settling for quicktime as it is seems to suffer the least from these issues.

I would love to hear any input you might have. We are shooting dress on Wednesday and will try a few more things before then.

Not sure I have anything to offer, sorry.
It seems that your machine should be able to handle playback (first reading I thought video card?)
I don't have any slow clear pan type videos to do a test with, so I can't even confirm the behavior locally (Unless you want to drop box it to me?)

Well we just finished up the run. Super fun. The piece was very well received.

In the work, I found that the Native Windows player introduced a few issues:

I found that it dropped a lot of frames

I found that it would randomly not play clips. If I had 2 or three clips in a scene, it would play the first two but not the third. If I restarted Isadora, it would play them fine until this issue popped up again.

With these two issues present, I went back to using quicktime as it was much more reliable and it dropped less frames.

I can't say I have noticed frame-drops, but that may be due in part to the style of many of my videos.
but videos not playing, I think I have come across this bug before, and found a work around.. This should probably be looked into in more detail.
I will run some tests.. if I remember correctly there is a case were the video player does init and requires a quick switch of a playback parameter.